Elias Salleh

Daylight ratio, luminance, and visual comfort assessments in typical malaysian hostels

Conventional tropical building designs are experiencing a new paradigm in their environmental response to improve lighting ambiance and occupants’ visual comfort through the exploitation of daylighting. However, it is important for architects to understand that flaws in daylighting strategies could lead to disadvantages as they could hinder vision, cause discomfort, increase interior heat gain, and result in excessive energy demands. The objective of this study was to assess how occupants’ perceived their visual conditions through daylight ratio and luminance level measurements. Measurements were conducted throughout a 2-month period starting from 12th May to 3rd July 2007. Three case studies were conducted at typical Malaysian hostels located in the Klang Valley. Those selected were: the Twelfth Residential College, Universiti Malaya (H1); the Eleventh Residential College, Universiti Putra Malaysia (H2); and Murni Student Apartments, Universiti Tenaga Nasional (H3). The daylighting source in all these case studies were from side-lit windows. Overall, the findings suggested that occupants were at ease with the level of daylighting available in their rooms even though rooms that were shaded by projecting balconies (i.e.,: H1) were dimmer than the rooms that were not shaded (i.e.,: H2 and H3).

A state of the art review of solar walls: Concepts and applications

Sustainable energy system design offers credible and innovative strategies to overcome environmental energy crises. Solar walls offer feasible technique for the exploitation of directional flow of heat in buildings. This article reviewed state-of-the-art concepts, applications and significance of solar walls for energy savings in buildings. Detailed operational framework of various solar-wall configurations, technology and efficiency as building component was discussed. Need for this sustainable energy design in buildings and constraints associated with their realisation were reported to aid proposed future research work.

A thermal comfort investigation of a facility department of a hospital in hot-humid climate: Correlation between objective and subjective measurements

A field study on assessing thermal comfort has been performed on one of the large-scale hospitals in Malaysia, a country where the climate is classified as hot-humid. The main objective of this study was to examine the comfort criteria by American Society of Heating, Air conditioning & Refrigeration Engineers, US (ASHRAE) standards in hot-humid regions and also to find the correlation between predicted mean vote (PMV) according to Fanger’s theory and thermal sensation vote (TSV) according to occupant votes. Therefore, both objective and subjective data was collected in this hospital, and this study’s results have confirmed that the preferred temperature is not necessarily in compliance with a neutral temperature, and people in hot-humid areas would prefer cooler environment to neutral temperature. In addition, by analyzing linear regression, a strong correlation between PMV and TSV was found while R2 = 0.950, and also the neutral temperature point in this field study was around +0.75 on the seven-point ASHRAE thermal sensation scale.

The Prediction of Drying Uniformity in Tray Dryer System using CFD Simulation

Tray dryer is the most extensively used because of its simple and economic design. In a tray dryer, more products can be loaded as the trays are arranged at different levels. The product is spread out on trays at an acceptable thickness. The drawback of this dryer is non-uniformity in the desired moisture content of end product due to poor air flow distribution in the drying chamber. Computational fluid dynamics (CFD) is used extensively because of its capability to solve equations for the conservation of mass, momentum, and energy using numerical methods to predict the temperature, velocity, and pressure profiles. This research is to predict drying uniformity of new design of the commercial tray dryer for agricultural product. The temperature and velocity profile, streamline and velocity on each tray was analysed to study the uniformity of the drying. The 3D simulation is done to represent the actual model. Generally the temperatures are considered uniform for all trays. However the average air velocity at several trays which is at tray number 1,7,8 and 15 are much higher than others tray. The rest of the trays are look more uniform. The average air velocity above the tray is about 0.38 m/s.

Design and Modeling of One Refrigeration Ton Solar Assisted Adsorption Air Conditioning System

The modeling of the performance of a one refrigeration ton (RT) solar assisted adsorp-tion air-conditioning refrigeration system using activated carbon fiber/ethanol as theadsorbent/adsorbate pair has been undertaken in this study. The effects of hot water,cooling water, chilled water inlet temperatures, and hot water and chilled water flowrates were taken into consideration in the optimization of the system and in the design ofthe condenser, evaporator, and hot water storage tank. The study includes analysis of theweather data and its effect on both the adsorption system and the cooling load. This isthen followed by estimation of the cooling capacity and coefficient of performance (COP)of the adsorption system as a function of the input parameters. The results of the modelwill be compared to experimental data in a next step. [DOI: 10.1115/1.4027964]Keywords: solar energy, adsorption air conditioning, activated carbon fiber/ethanol,cooling load

The Effect of Drying Air Temperature and Humidity on the Drying Kinetic of Kenaf Core

Drying kinetics of kenaf core was investigated in a Low Temperature and Humidity Chamber Test. The drying experiments were carried out at temperature of 45, 50 and 55°C and air relative humidity of 10, 20 and 30% using a constant air velocity of 1.0 m/s. The moisture content data at various drying air conditions were converted to moisture ratio and plotted against time to obtain the drying curves for each experimental data. The curves were fitted to eight different thin layer drying models to determine a suitable model for drying of kenaf core. The fit quality of the models was evaluated based on their coefficient of determination (R2), reduced chi-square (χ2) and root mean square error (RMSE). Among the eight models, Two Term model is the best model for describing the drying behavior of kenaf core. The drying air temperature gave more significant effect on the drying kinetic of kenaf core compared to the drying air relative humidity under the experimental conditions studied.

The CFD Simulation of Tray Dryer Design for Kenaf Core Drying

Tray dryer is the most extensively use for kenaf core drying because of its simple and economic design. The product is spread out on trays at an acceptable thickness so that the product can be dried uniformly. Most tray dryers use hot air stream where water is vaporized from the product and removed by air stream. In a tray dryer, more products can be loaded as the trays are arranged at different levels. The drawback of this dryer is non-uniformity in the desired moisture content of end product. The key to the successful operation of the tray dryer is uniform airflow distribution over the trays. Therefore, the good design of the drying chamber configuration in a tray dryer is necessary to obtain optimum performance. This research is to design the uniform airflow distribution throughout the drying chamber using CFD simulation for kenaf core drying. Several configurations of drying chamber and trays position was designed and simulated to determine the tray dryer which can produce better airflow distribution. It was found that the design B gives a more uniform airflow distribution compared to others design. The good design of kenaf core dryer should be able to produce uniform drying at high drying capacity and shorter drying time.

Affordable housing design with application of vernacular architecture in Kish Island, Iran

Purpose - Kish Island is one of the most attractive tourism destinations in Iran and it is becoming an increasingly popular destination for tourism investment. Many people have recently migrated to the island. Thus, one of the housing policies for the island is to maximize the efficiency of residential lands, particularly in providing affordable housing for low-income people. The purpose of this study is to develop social, economical and architectural solutions for affordable housing design and overcome related problems using adapted vernacular solutions. Design/methodology/approach - The methodology of this study involved identifying the research problem, followed by formatting the research framework, reviewing the comprehensive literature and documenting the concepts of affordable housing and vernacular architecture. Therefore, an affordable house design methodology was used to develop vernacular architecture to minimize cost and environmental impacts, while maximizing the social acceptability in housing projects for low-income earners in Kish Island. Section A in Mir Mohanna, which is the most important residential centre for the low-income people, was used as the study area in this research. Findings - The results of this study clarified that the houses in Section A in Mir Mohanna did not meet the criteria of affordable housing and peoples needs. Hence, some suggestions for affordable housing would certainly contribute towards formulating all these, including housing policy to be implemented on Kish Island. Originality/value - The current paper was an attempt to find strategies for guiding the appropriate process of developing affordable housing on the basis of vernacular architecture for the country and other similar places. It is hoped that the recommendations might increase more regulated housing development and housing policies on Kish Island.

Heat Removal Factor of an Unglazed Photovoltaic Thermal Collector with a Serpentine Tube

Heat removal factor (F R ) is a vital parameter in determining the thermal efficiency of a photovoltaic thermal (PVT) system. As a main factor of thermal performance, F R represents the ratio of the actual heat transfer to the maximum yield of heat transfer. In this study, F R of an unglazed PVT with serpentine tube collector was determined, with focus on the flat-plate thickness of the flat-plate serpentine tubes. Thermal modeling was used to estimate the overall heat losses of the unglazed PVT. The highest F R value of 0.88 was obtained in the 0.015-m-thick flat plate, followed by 0.84 in the 0.010-m-thick flat plate. The difference in F R between the two designs was only 4.54 %, which can be considered within the acceptable range for the flat-plate thickness. This consideration was based on an economic point of view and the handling issues of PVT systems.

Validation of Thermal Modelling for the Back Surface Temperature of a Photovoltaic Module for Hot and Humid Climate

Thermal modeling is one of the approaches used to assess the performance of photovoltaic thermal. The main objective of this study is to validate thermal modeling by using the experimental results to estimate the back surface temperature of a photovoltaic module in hot and humid climate. Several assumptions have been made to simplify the analysis base on energy balance method. Good agreement is observed between the experiment and thermal modeling, with a correlation coefficient (r) and root mean square percent deviation of 0.931 and 12.1% respectively.